Heating system component and method for producing same

ABSTRACT

The present disclosure relates to a heating system component including a temperature monitoring and/or control unit comprising a lower surface, and a carrier unit comprising an upper surface. At least a part of said lower surface of said temperature monitoring and/or control unit is in thermal contact with at least a part of said upper surface of said carrier unit. Said lower surface of said temperature monitoring and/or control unit and said upper surface of said carrier unit are attached to each other by means of a welded seam, preferably by means of a laser-welded seam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/747,913, filed Jun. 23, 2015, which claims priority from and thebenefit of European Patent Application No. 14173711.4-1602, filed Jun.24, 2014, and European Patent Application No. 15173012.4, filed Jun. 19,2015, each of which is hereby incorporated by reference for all purposesas if fully set forth herein.

BACKGROUND

Technical Field

The present disclosure relates to a heating system component, to aheating system for heating fluid media, and to a method for producing aheating system component.

Description of the Related Art

For many types of domestic appliances or domestic machines, it isnecessary to heat up a fluid medium, such as for example water. Heatingup can be caused by means of one or more heating systems. To thatextent, a medium circuit can be provided, a pump arranged in the circuitcausing circulation of the medium in the circuit.

Basic aspects of such heating systems are that, like all othercomponents of the medium circuit, the system is to take up only a smallamount of space and is to be inexpensive to produce. Furthermore, theheating system shall be simple to assemble. Reliable safeguarding of theheating system must be guaranteed upon the occurrence of a criticaloperating condition which can result in plastic components within thedomestic appliance melting or catching fire. In case of some domesticappliances, it may further be necessary to prevent the medium to beheated from exceeding a predetermined temperature. For example in thecase of a dishwashing machine, it may be necessary to prevent thewashing water from exceeding its boiling temperature.

US patent application 2006/0236999 A1 discloses a heating system forheating fluid media, in particular for domestic appliances, including acarrier unit, a heating unit arranged on the carrier unit and a heattransfer element which is arranged on the carrier unit and comprising amaterial which is a good conductor of heat. On the heat transferelement, temperature safety devices are mounted by fixing elements viacorresponding through apertures.

When using conventional temperature monitoring and/or control elements(such as, e.g., thermal fuses) with continuous-flow water heaters, thereis a problem when the temperature monitoring and/or control elements arefixed with, e.g., one or more screws, to a mounting plate. That is, whenthe mounting plate is soldered to the heating unit, it may curve.Further, when fastening respective fixing screws on a temperaturemonitoring and/or control element, the temperature monitoring and/orcontrol element may be lifted from the fixing plate and remain in theair above the hot location. As a consequence, the largest amount of heatin the center of the heating unit cannot be released directly to thetemperature monitoring and/or control element, but has to be releasedvia, e.g., the mounting plate, screws, and/or the base plate flange.These effects result in an unacceptable (i.e., too slow) response timeof the temperature monitoring and/or control element.

BRIEF SUMMARY

Embodiments of the present invention provide a heating system component,a heating system, and a method for producing a heating system component,which avoid the slow response times of prior-art arrangements.

According to a first aspect of the present invention, there is provideda heating system component comprising: a temperature monitoring and/orcontrol unit comprising a lower surface; a carrier unit comprising anupper surface; wherein at least a part of said lower surface of saidtemperature monitoring and/or control unit is in thermal contact with atleast a part of said upper surface of said carrier unit; wherein saidlower surface of said temperature monitoring and/or control unit andsaid upper surface of said carrier unit are attached to each other bymeans of a welded seam, preferably by means of a laser-welded seam.

Embodiments of the present invention propose to fix the temperaturemonitoring and/or control element onto the heating unit, preferably inthe direct vicinity of the hottest spot thereof, by means of a weldedseam. Preferably, the fixing is carried out by welding, in particular bylaser welding. In general, employing laser welding for attachingtemperature monitoring and/or control elements in heating systemsinvolves the advantage of higher functionality and security as comparedto prior art mounting approaches using, e.g., curved spring washers. Inparticular, fixing the temperature monitoring and/or control elementonto the heating unit by welding significantly improves (i.e., reduces)the temperature monitoring and/or control element's response time.

According to a preferred embodiment, said temperature monitoring and/orcontrol unit comprises a lower part having a beveled edge; wherein saidbeveled edge is adjacent to said lower surface; wherein said bevelededge comprises a bevel angle of less than 90°; wherein said welded seamis located essentially along said beveled edge. By employing a bevelededge having a bevel angle of less than 90°, it is easier to reach thecontact area between the temperature monitoring and/or control unit'slower surface and the carrier unit's upper surface with a laser beam. Asa consequence, less laser power is needed, while still achieving thedesired strength of attachment between the temperature monitoring and/orcontrol unit's lower surface and the carrier unit's upper surface.

During the use of a heating system, it is possible that scale or calciumis deposited on the side of the carrier unit being in contact with thefluid medium to be heated, like water, in particular in the area of thecarrier unit when the heating unit is arranged on the other side of thecarrier unit. Due to this calcium deposit, the transfer of the heatgenerated by the heating unit, can be impaired. Thus, the temperaturemonitoring and/or control element can detect a temperature being higherthan a temperature without such a calcium deposit. In some cases, thetemperature monitoring and/or control element can then cut-off theelectricity supply to the heating unit although the medium is stillpresent, i.e. the temperature monitoring and/or control unit detects asafety relevant situation, like a dry run. In order to avoid this, itcould be of advantage to provide a connection to the thermal monitoringand/or control element such that the connection is in contact with anarea of carrier unit being spaced to the heating unit. Through this, thetemperature monitoring and/or control unit can be cooled by the mediumso that the temperature detection is not impaired by the calcium depositon the carrier unit in the area of the heating unit. This connection canalso be laser-welded to the carrier unit wherein the connection can alsobe provided with a beveled edge. The dimensions of that connection canbe chosen in accordance with the need to cool the temperature monitoringand/or control unit.

Moreover, it is also possible to attach the temperature monitoringand/or control unit directly on the top surface of the heating unit.

According to a further preferred embodiment, said bevel angle rangesbetween 5° and 55°, preferably between 15° and 45°, and even morepreferably between 25° and 35°. By choosing a bevel angle as described,reaching the contact area between the temperature monitoring and/orcontrol unit's lower surface and the carrier unit's upper surface with alaser beam is made even easier and thus improved. Further, by increasingthe respective melting zone, a complete material connection can beachieved. Providing a beveled edge of a certain length in additioncompensates for a potential mispositioning during automatic production.When aiming for a laser entrance angle on the material surface of 90°, abevel angle of preferably 30° may be chosen so that the laser beam canbe directed at an angle of 120° with respect to the carrier unit's uppersurface. The laser beam can thus be prevented from getting too close tothe sensitive parts of the temperature monitoring and/or control unit.

According to a further preferred embodiment, said temperature monitoringand/or control unit is configured to measure a temperature, to comparesaid temperature to a predefined temperature limit, and to output acontrol signal based on said comparison.

According to a further preferred embodiment, said control signalcomprises information on a desired switching state of a heating unit.

According to a further preferred embodiment, said lower surface of saidtemperature monitoring and/or control unit comprises at least one firstprotrusion and/or recess. Said upper surface of said carrier unitcomprises at least one second recess and/or protrusion. Said firstprotrusion and/or recess corresponds to said second recess and/orprotrusion. By designing the temperature monitoring and/or controlunit's lower surface and the carrier unit's upper surface in thedescribed manner, the total contact area can be increased, thusproviding for an improved heat transport between carrier unit andtemperature monitoring and/or control unit. The design further enablesan easier manufacture given the preferred matching of protrusions andrecesses.

According to a further preferred embodiment, said lower surface of saidtemperature monitoring and/or control unit comprises AlMg3. However, anyother weldable aluminum alloys or aluminum-steel compound material canbe used.

According to a further preferred embodiment, said upper surface of saidcarrier unit comprises AlMg3. However, aluminum alloys Al99.5 and AlMg1are suitable as well.

According to a further preferred embodiment, said temperature monitoringand/or control unit comprises at least one temperature monitoring and/orcontrol element having a lower surface which is smaller than said lowersurface of said temperature monitoring and/or control unit. By designingthe temperature monitoring and/or control element such that it comprisesa lower surface which is smaller than said lower surface of saidtemperature monitoring and/or control unit, it is possible to have thelower surface of said temperature monitoring and/or control unitextending beyond the lower surface of said temperature monitoring and/orcontrol element. The temperature monitoring and/or control unit's lowersurface can thus be reached in an easier manner in order to attach thetemperature monitoring and/or control unit to the carrier unit.

According to another aspect of the present invention, there is provideda heating system for heating fluid media, in particular for domesticappliances, comprising: a heating system component as described herein,a heating unit arranged on said carrier unit, and wherein saidtemperature monitoring and/or control unit is configured to measure thetemperature of said heating unit.

According to a preferred embodiment, the heating system comprises acasing portion, wherein the heating unit is mounted to said casingportion, and wherein the casing portion comprises aluminum. Even morepreferably, the entire heating system is composed of aluminum. Whereasconventional heating systems typically provide a recess in a carrierunit, where the heating unit is arranged within the recess, thepreferred embodiment described herein advantageously makes it possibleto mount (e.g., by soldering) a heating unit directly to a casingportion of the carrier unit. The carrier unit is thus structurallysimplified, because a recess is no longer necessary. Further, the innerside of the casing portion is preferably coated with a nonstick coating.The nonstick coating is preferably composed of a ceramics-basedmaterial. By employing a ceramics-based nonstick coating, the aluminumsurfaces may be rendered dishwasher-safe.

According to a preferred embodiment, the heating unit comprises a heattransfer element, wherein said heat transfer element is an elongate flatelement. According to a further preferred embodiment, the carrier unitcomprises a disc. According to a further preferred embodiment, thecarrier unit has a recess which is open at one side and which ispreferably at least approximately C-shaped in cross-section forreceiving the heating unit. According to a further preferred embodiment,the heating unit is formed by at least one tubular heater. According toa further preferred embodiment, the cross-sectional shape of the heatingunit is at least approximately adapted to the cross-sectional shape ofthe recess of the carrier unit.

According to another aspect of the present invention, there is provideda method for producing a heating system component as described herein.The method comprises: providing a temperature monitoring and/or controlunit comprising a lower surface; providing a carrier unit comprising anupper surface; contacting at least a part of said lower surface of saidtemperature monitoring and/or control unit with at least a part of saidupper surface of said carrier unit; welding, preferably laser-welding,said lower surface of said temperature monitoring and/or control unitand said upper surface of said carrier unit to each other.

According to a preferred embodiment, the method further comprisesbeveling an edge of a lower part of temperature monitoring and/orcontrol unit to obtain a beveled edge, wherein said beveled edgecomprises a bevel angle of less than 90°; wherein said welding iscarried out essentially along said beveled edge. According to a furtherpreferred embodiment, said welding comprises laser-welding by employinga laser beam, and said laser beam is directed essentially perpendicularto a surface of said temperature monitoring and/or control unit.According to a further preferred embodiment, said laser beam comprises apower of between 0.5 kW and 1.5 kW, preferably of 1 kW.

It shall be understood that the heating system components, the heatingsystems for heating fluid media, and the methods for producing a heatingsystem component described herein may have similar and/or identicalaspects.

It shall be understood that a preferred embodiment of the invention canalso be any combination of features set forth in the claims.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings:

FIG. 1 shows schematically and exemplarily a perspective sectional viewof part of a prior-art heating system;

FIG. 2 shows schematically and exemplarily a cross sectional view ofpart of a prior-art heating system;

FIG. 3 shows schematically and exemplarily a top view of a temperaturemonitoring and/or control element;

FIG. 4 shows schematically and exemplarily a top view of a temperaturemonitoring and/or control elements' base plate;

FIGS. 5A to 5C show schematically and exemplarily an embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements;

FIG. 6 shows schematically and exemplarily another embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements;

FIG. 7 shows schematically and exemplarily an embodiment of atemperature monitoring and/or control element having a bevel ofapproximately 30°;

FIG. 8 shows schematically and exemplarily another view of thetemperature monitoring and/or control element of FIG. 7;

FIG. 9 shows schematically and exemplarily a beveled edge of atemperature monitoring and/or control element after welding;

FIG. 10 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements;

FIG. 11 shows schematically and exemplarily an exploded view of a detailfrom the temperature monitoring and/or control system of FIG. 10;

FIG. 12 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements;

FIG. 13 shows schematically and exemplarily another view of thetemperature monitoring and/or control system of FIG. 12; and

FIG. 14 shows schematically and exemplarily a further embodiment of thetemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements;

FIG. 15 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements;

FIG. 16 shows schematically and exemplarily an embodiment of a methodfor producing a heating system component.

DETAILED DESCRIPTION

One concern with heating systems is reliable safeguarding againstoverheating. Typically, protection against overheating is achieved byemploying temperature monitoring and/or control elements, such as, e.g.,thermostats and/or thermal links. Temperature monitoring and/or controlelements tend to be used in applications where a fixed temperature needsto be monitored or controlled and a maximum temperature must not beexceeded. Example applications include, but are not limited to,household appliances such as dishwashers and washing machines, smallelectrical appliances such as coffeemakers, steam generators etc. orelectrically monitored water heaters.

As a temperature sensing element, e.g., a vaulted bimetal disc may beused. The vaulted bimetal disc is preferably placed in direct contactwith a mounting plate therefore reacting quickly to temperature. Havingreached a predetermined temperature the bimetal disc operates and opensan electrical circuit. Once the temperature has fallen again under thepredetermined temperature, the disc returns into its original positionthereby closing the circuit again. Additionally and/or alternatively, asolder insert in the mounting plate may be in direct thermal contactwith the surface that is to be monitored. When the preset temperature isreached, the solder melts causing a pin to move which results in theelectrical contacts opening. For a two-component system combiningtemperature monitoring and temperature control, the two componentstemperature monitor and temperature control may have a common mountingplate, which is responsible for thermal conduction. This ensures thatthe thermal information for thermostat and thermal link always comesfrom the same source.

Temperature control elements may be used for applications where amaximum temperature must not be exceeded (such as, e.g., for example incoffee makers, irons, dishwashers, dryers) and to protect electricheating elements. A temperature control element typically has a meltsolder insert in the mounting plate which is in direct thermal contactwith the surface that is to be monitored. When the preset temperature isreached, the solder melts causing a pin to move which results in theelectrical contacts opening.

FIG. 1 shows schematically and exemplarily a conventional heating systemas disclosed in US patent application 2006/0236999 A1, which isincorporated herein by reference. The heating system of FIG. 1 comprisesa carrier unit T, a heating unit H, a heat transfer element W, andsafety devices S1, S2 arranged on the heat transfer element W. The firstsafety device S1 interrupts the power circuit to the heating unit H,based on the temperature of the heating unit H, which is detected by thefirst safety device S1. First safety device S1 preferably interrupts thepower circuit to the heating unit H when the temperature of the heatingunit H exceeds a first predetermined temperature limit value, forexample when the heating unit H runs dry. The first predeterminedtemperature limit value may be chosen such that melting of plastic partsin the region of the heating system is avoided. The second safety deviceS2 interrupts the power circuit to the heating unit H based on thetemperature of the medium to be heated, which is detected by the secondsafety device S2. Second safety device S2 preferably interrupts thepower circuit to the heating unit H when the temperature of the mediumto be heated exceeds a second predetermined temperature limit valuewhich can be defined for example by the boiling temperature of themedium to be heated. Consequently the medium is prevented from boiling.Safety devices S1, S2 may be considered temperature monitoring and/orcontrol elements.

The heating system may be connected to, e.g., a conveyor pump of adishwashing machine, of which only the housing PG comprising a plasticmaterial with a low melting point is shown in part in FIG. 1. Theheating system can be mounted to the conveyor pump or the housing PGthereof during assembly of the domestic appliance or can form apre-assembled structural unit together with the conveyor pump.

As can be seen from FIG. 1, carrier unit T is a circular disc 10 whichmay be produced, e.g., from corrosion-resistant steel. In concentricrelationship with its central axis (not shown) disc 10 has a circularhole 12, through which the suction pipe of the pump is passed in sealingintegrity in relation to the medium. At its outer peripheral edge 14,disc 10 may engage over the edge of the pump housing PG in sealingintegrity in relation to the medium. That side of disc 10, which facesin the direction of the lower edge of the sheet in FIG. 1, is in directcontact with the medium to be heated in the installed condition of thepump and can therefore be referred to as the wet side whereas the sideof the disc 10, which faces towards the upper edge of the sheet, doesnot come into contact with the medium and can thus be referred to as thedry side.

As can further be seen from FIG. 1, disc 10 forming carrier unit T has arecess 16 which extends there around in concentric relationship with itscentral axis at approximately the radial center of the disc 10. Recess16 is of a square configuration in cross-section, wherein one side ofthe square, being the upwardly facing side, is omitted. Heating unit Hwhich is formed by a tubular heater of known kind is fitted in therecess 16. As can be seen from FIG. 1, the shape and the outsidedimensions of heating unit H are matched to the shape and the outsidedimensions of recess 16 in disc 10 in such a way that heating unit H isin full area contact at three sides against the inside walls (notidentified in greater detail) of recess 16. Consequently, heat producedby heating unit H is transferred to the medium which is disposed on thewet side of disc 10 and which is to be heated.

When using conventional temperature monitoring and/or control elements(such as, e.g., thermal fuses) with continuous-flow water heaters, thereis a problem when the temperature monitoring and/or control elements arefixed with, e.g., one or more screws, to a mounting plate, as shown inFIG. 1 for the prior-art heating system shown therein. That is, when themounting plate is soldered to the heating unit, it may curve. Further,when fastening respective fixing screws on a temperature monitoringand/or control element, the temperature monitoring and/or controlelement may be lifted from the fixing plate and remain in the air abovethe hot location. This effect is illustrated in FIG. 2 and indicated byan arrow. As a consequence, the largest amount of heat in the center ofthe heating unit cannot be released directly to the temperaturemonitoring and/or control element, but has to be released via, e.g., themounting plate, screws, and/or the base plate flange. These effectsresult in an unacceptable (i.e., too slow) response time of thetemperature monitoring and/or control element.

One idea to address the above-identified issue is to directly fix thetemperature monitoring and/or control element onto the heating unit,preferably in the direct vicinity of the hottest spot thereof. Thefixing may be carried out by welding, preferably by laser welding. Ingeneral, as set out in the following, employing laser welding forattaching temperature monitoring and/or control elements in heatingsystems involves the advantage of higher functionality and security ascompared to prior art mounting approaches using, e.g., curved springwashers. In particular, fixing the temperature monitoring and/or controlelement onto the heating unit by welding significantly improves (i.e.,reduces) the temperature monitoring and/or control element's responsetime.

Several examples for fixing the temperature monitoring and/or controlelement onto the heating unit by welding are illustrated in thefollowing. FIG. 3 shows schematically and exemplarily one option to fixthe temperature monitoring and/or control element onto the heating unitby welding. That is, FIG. 3 shows a temperature monitoring and/orcontrol element 310. A spot weld 330 on respective mounting portions ofmonitoring and/or control element 310 is illustrated as well. FIG. 4shows schematically and exemplarily another option to fix thetemperature monitoring and/or control element onto the heating unit bywelding. That is, FIG. 4 shows a top view of a temperature monitoringand/or control elements' base plate comprising weld seams 530.

FIG. 5A shows schematically and exemplarily an embodiment of atemperature monitoring and/or control system 500 comprising temperaturemonitoring and/or control elements 510 a, 510 b. Temperature monitoringand/or control elements 510 a, 510 b are mounted on a carrier unit 520.As further shown in the detailed view of area D of the left panel ofFIG. 5A, Temperature monitoring and/or control elements 510 a, 510 b aremounted to carrier unit 520 via weld seams 530.

FIGS. 5B and 5C show schematically and exemplarily further views oftemperature monitoring and/or control system 500. The heating system ofFIGS. 5A to 5C comprises a carrier unit 520, a heating unit 500-H, aheat transfer element 500-W, and temperature monitoring and/or controlunits 510 a, 510 b, which may preferably be safety devices. Temperaturemonitoring and/or control units 510 a, 510 b are arranged on heattransfer element 500-W. A first temperature monitoring and/or controlunit 510 a interrupts the power circuit to the heating unit 500-H, basedon the temperature of the heating unit 500-H, which is detected by thefirst temperature monitoring and/or control unit 510 a. Firsttemperature monitoring and/or control unit 510 a preferably interruptsthe power circuit to heating unit 500-H when the temperature of heatingunit 500-H exceeds a first predetermined temperature limit value, forexample when heating unit 500-H runs dry. The first predeterminedtemperature limit value may be chosen such that melting of plastic partsin the region of the heating system is avoided. A second temperaturemonitoring and/or control unit 510 b interrupts the power circuit toheating unit 500-H based on the temperature of the medium to be heated,which is detected by second temperature monitoring and/or control unit510 b. Second temperature monitoring and/or control unit 510 bpreferably interrupts the power circuit to heating unit 500-H when thetemperature of the medium to be heated exceeds a second predeterminedtemperature limit value which can be defined for example by the boilingtemperature of the medium to be heated. Consequently the medium isprevented from boiling.

The heating system may be connected to, e.g., a conveyor pump of adishwashing machine in a similar manner as the heating system shown inFIG. 1. The heating system can be mounted to the conveyor pump or to ahousing thereof during assembly of the domestic appliance or can form apre-assembled structural unit together with the conveyor pump.

As can be seen from FIGS. 5A to 5C, carrier unit 520 is a circular disc500-10 which may be produced, e.g., from corrosion-resistant steel.However, in other embodiments of carrier unit 520, circular disc 500-10may be produced, e.g., from AlMg3, AlMg1, or Al99.5. In concentricrelationship with its central axis (not shown) disc 500-10 has acircular hole 500-12, through which the suction pipe of the pump ispassed in sealing integrity in relation to the medium. At its outerperipheral edge, disc 500-10 may engage over the edge of a pump housingin sealing integrity in relation to the medium. That side of disc500-10, which faces in the direction of the lower edge of the sheet inFIGS. 5A to 5C, is in direct contact with the medium to be heated in theinstalled condition of the pump and can therefore be referred to as thewet side whereas the side of the disc 500-10, which faces towards theupper edge of the sheet, does not come into contact with the medium andcan thus be referred to as the dry side.

Disc 500-10 forming carrier unit 520 preferably has a recess whichextends there around in concentric relationship with its central axis atapproximately the radial center of disc 500-10. Said recess ispreferably of a square configuration in cross-section, wherein one sideof the square, being the upwardly facing side, is omitted. Heating unit500-H which is preferably formed by a tubular heater of known kind isfitted in the recess. The shape and the outside dimensions of heatingunit 500-H are preferably matched to the shape and the outsidedimensions of the recess in disc 500-10 in such a way that heating unit500-H is in full area contact at three sides against the inside walls ofsaid recess. Consequently, heat produced by heating unit 500-H istransferred to the medium which is disposed on the wet side of disc500-10 and which is to be heated.

As can further be seen from FIGS. 5B and 5C, a laser beam 540 may beemployed to attach temperature monitoring and/or control units 510 a,510 b to carrier unit 520. In particular, respective lower parts oftemperature monitoring and/or control units 510 a, 510 b may comprisebeveled edges 550 a, 550 b. By employing a beveled edge 550 a or 550 b,laser beam 540 can be directed such that it is prevented from gettingtoo close to sensitive parts of temperature monitoring and/or controlunits 510 a, 510 b. A welded seam 530 a, 530 b is established alongbeveled edges 550 a, 550 b. Further details are explained herein below.

FIG. 6 shows schematically and exemplarily another embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements 510 a, 510 b mounted on a tube filedwith a fluid to be heated, such as, e.g., a water pipe. Temperaturemonitoring and/or control elements 510 a, 510 b are fixed to the tube bymeans of laser weld seams 530.

In order to illustrate the effect of welding the temperature monitoringand/or control elements to the carrier unit, several test measurementshave been carried out. In a first test experiment, a temperaturemonitoring and/or control element was fixed to a continuous-flow waterheater by (a) pressing and (b) laser-welding. The test yielded aresponse time of the laser-welded temperature monitoring and/or controlelement which was two to four seconds shorter than the correspondingresponse time of the pressed temperature monitoring and/or controlelement. In addition, for case (b) overshoot was reduced byapproximately 20° C.

In a further test experiment, there occurred a problem that, when fixingthe temperature monitoring and/or control element to the base plate of acontinuous-flow water heater, a high laser power of up to 2 kW (or evenmore) was necessary due to a disadvantageous laser entry angle. Thisyields an unsatisfactory welding result. One solution to improve thelaser entrance into the base plate material (which may be preferablyAlMg3) is illustrated in FIGS. 7 and 8 and relates to employing a bevel910 (i.e., a beveled edge connecting the two adjacent surfaces) ofpreferably 25° to 35° at wing ends 920 of temperature monitoring and/orcontrol element 930. Bevel 910 is preferably punched or stamped intowing ends 920. Punching or stamping is preferably carried out by meansof a punch cutter or stamping tool, respectively.

Employing bevel 910 makes it easier for laser beam 540 to enter thematerial at a preferred angle of 90°. As a consequence of laser beam 540entering at a more preferred angle, the welds turn solid and the meltenters the carrier plate 940 and wing ends 920 preferably in acone-shaped manner. The conical entering of melt 1110 in the directionof the laser beam is shown in FIG. 9. In the test experiment described,a laser power of 1 kW was sufficient when using a 45°-bevel. Asexplained herein above, a bevel of 25° to 35° degrees is even morepreferred. By applying a bevel to the wing ends of the temperaturemonitoring and/or control element, the laser power necessary tosatisfactorily mount the temperature monitoring and/or control elementcan thus be reduced.

An optimal thermal coupling of temperature monitoring and/or controlelement to the heating system results in an improved heat transfer andshorter response time. Consequently, strong heating powers can becontrolled in a secure manner and positive effects on scaling of thetubes are observed. By welding the temperature monitoring and/or controlelement to the heating system, less mounting elements are needed,because, e.g., fixing elements, such as, e.g., screws, may be omitted.Accordingly, the mounting is eased in general. Automating the couplingprocess is possible as well. In accordance with the improved thermalcoupling, a higher temperature threshold of the temperature monitoringand/or control element may be chosen. Consequently, the temperaturemonitoring and/or control system is rendered more robust overall in viewof a potential formation of scale of the heating surface.

FIG. 10 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements. In the embodiment of FIG. 10, cutoutportion 1050 is provided in carrier plate 940. By means of cutoutportion 1050, it is possible to define the quantity of heat transferredfrom a heat transfer element on carrier plate 940 to temperaturemonitoring and/or control element 930 a. That is, by making cutoutportion 1050 larger, the cross section area available for conductingheat is made smaller so that less heat is transferred to temperaturemonitoring and/or control element 930 a. Alternatively, by making cutoutportion 1050 smaller, the cross section area available for conductingheat is made larger so that more heat is transferred to temperaturemonitoring and/or control element 930 a. Defining the heat quantity tobe conducted to temperature monitoring and/or control element 930 a maybecome necessary in order to account for the improved thermal couplingdue to laser welding. That is, when pressing a conventional temperaturemonitoring and/or control element on a carrier plate, less heat istransferred to the conventional temperature monitoring and/or controlelement. The temperature monitoring and/or control element's temperaturethresholds are accordingly adjusted to trigger when a certain amount ofheat has been received. With the improved thermal coupling according toembodiments of the present invention, that certain amount of heat isconducted to the temperature monitoring and/or control element muchfaster. In order to avoid having to adjust the respective temperaturethresholds, one may thus consider including cutout portion 1050 asdescribed herein.

FIG. 11 shows schematically and exemplarily an exploded view of a detailfrom the temperature monitoring and/or control system of FIG. 10.Temperature monitoring and/or control element 930 is shown on the top.Carrier plate 940 comprising cutout portion 1050 is shown in the center.The mounted combination of temperature monitoring and/or control element930 and carrier plate 940 is shown in the bottom, where cutout portion1050 is visible as well.

FIG. 12 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system comprising temperaturemonitoring and/or control elements. The temperature monitoring and/orcontrol system differs from the temperature monitoring and/or controlsystems discussed above in that its construction is optimized for anall-aluminum option.

In particular, there are shown temperature monitoring and/or controlelements 1230 a, 1230 b. Preferably, temperature monitoring and/orcontrol elements 1230 a, 1230 b are laser-welded onto thermal bridge1280. Thermal bridge 1280 is preferably composed of AlMg3. However,aluminum alloys Al99.5 and AlMg1 are suitable as well. As shown in FIG.12, thermal bridge 1280 is preferably mounted on casing portion 1260.Casing portion 1260 is preferably composed of AlMg3. However, aluminumalloys Al99.5 and AlMg1 are suitable as well. Thermal bridge 1280 ispreferably mounted on casing portion 1260 by soldering or laser-welding.In FIG. 12, casing portion 1260 is shaped like a circular disc. However,other shapes of casing portion 1260 are conceivable to the skilledperson as well. Inner side 1270 of casing portion 1260 is preferablycoated with a nonstick coating. The nonstick coating is preferablycomposed of a ceramics-based material. Additionally and/oralternatively, the nonstick coating is preferably produced by means of asol-gel process. By employing a ceramics-based nonstick coating, thealuminum surfaces may be rendered dishwasher-safe. As can further beseen from FIG. 12, heating unit 1200-H is directly attached to casingportion 1260. In the embodiment shown, heating unit 1200-H exhibits atrapezoid cross-section. However, other cross section shapes of heatingunit 1200-H are conceivable to the skilled person. Heating unit 1200-His in full area contact with at least one of the inside walls of casingportion 1260. Consequently, heat produced by heating unit 1200-H istransferred to the medium which is disposed on the wet side of casingportion 1260 and which is to be heated.

FIG. 13 shows schematically and exemplarily another view of thetemperature monitoring and/or control system of FIG. 12. In theembodiment shown herein, an essential part of an upper surface ofheating unit 1200-H is soldered to casing portion 1260.

A list of possible manufacturing methods comprises, but is not limitedto, half-automatic assembly and fully-automatic assembly. The bevelededge geometry described herein is preferably optimized for an automaticpositioning of the temperature monitoring and/or control elementsaccording to embodiments of the present invention. That is, by choosinga bevel angle of preferably 25° to 35°, the bevel surface visible fromthe direction of laser beam 540 can be kept sufficiently large so that apossible misalignment of the temperature monitoring and/or controlsystem components can be compensated for.

FIG. 14 shows schematically and exemplarily an embodiment of a methodfor producing a heating system component. In a first step 1410, themethod comprises providing a temperature monitoring and/or control unitcomprising a lower surface. In a second step 1420, the method comprisesproviding a carrier unit comprising an upper surface. In a third step1430, the method comprises contacting at least a part of said lowersurface of said temperature monitoring and/or control unit with at leasta part of said upper surface of said carrier unit. In a further optionalstep 1450, the method comprises beveling an edge of a lower part of saidtemperature monitoring and/or control unit to obtain a beveled edge,wherein said beveled edge comprises a bevel angle of less than 90°. In afinal step 1440, the method comprises welding, preferably laser-welding,said lower surface of said temperature monitoring and/or control unitand said upper surface of said carrier unit to each other. Preferably,said welding is carried out essentially along said beveled edge obtainedin step 1450.

FIG. 14 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system being similar to theembodiment shown in and described in conjunction with FIGS. 5A to 5C.For the components of the embodiment according to FIG. 14 having anidentical or similar design and/or an identical or similar functionalitycompared to the components described in conjunction with the embodimentof FIGS. 5A to 5C, the same reference signs are used. Moreover, in thefollowing, only the differences between the embodiment according to FIG.14 compared to the embodiment described in conjunction with FIGS. 5A to5C are described.

As can be seen from FIG. 14, the temperature monitoring and/or controlsystem 500 of this embodiment comprises temperature monitoring and/orcontrol units 510 a, 510 b. The temperature monitoring and/or controlunit 510 b is additionally provided with a connection 540 connecting thelower surface of temperature monitoring and/or control unit 510 b with asection of circular disc 500-10 of carrier unit 520. Connection 540 isintegrally formed with the lower surface of temperature monitoringand/or control unit 510 b. The part or section of circular disc 500-10of carrier unit 520 is not heated directly by heating unit 500-H,instead it is cooled by the medium to be heated by heating unit 500-Hsince this medium flows on the other side of circular plate 500-10.Connection 540 can also be fixed to circular disc 500-10 bylaser-welding. Connection 540 is provided for a cooling of temperaturemonitoring and/or control unit 510 b in case that the transfer of theheat generated by heating unit 500-H is disturbed, for example, due to acalcium deposit on the outer surface of circular disc 500-10 of carrierunit 520 in the area of heating unit 500-H which is in contact with themedium. As can be seen from FIG. 14, connection 540 can be designed suchthat it follows the contour of the non-heated area of circular disc500-10 of carrier unit 520 when viewing in a cross-section. Moreover,connection 540 can be in the shape of a segment of a circle. The lengthof the arc of circle can be chosen in accordance with the need to cooltemperature monitoring and/or control unit 500 b.

FIG. 15 shows schematically and exemplarily a further embodiment of atemperature monitoring and/or control system being similar to theembodiment shown and described in conjunction with FIGS. 12 and 13. Forthe components of the embodiment according to FIG. 15 having anidentical or similar design and/or an identical or similar functionalityas the components shown in and described in accordance with theembodiments of FIGS. 12 and 13, same reference signs are used. Moreover,only the differences between the embodiments according to FIGS. 12 and13 and the embodiments of FIG. 15 are described.

As shown in FIG. 15, casing portion 1260 for receiving temperaturemonitoring and/or control units or elements 1230 a, 1230 b comprises arecess 1290 for receiving heating unit 1200-H. The contour of recess1290 corresponds to the outer contour of heating unit 500-H. In theembodiment shown in FIG. 15, heating unit 500-H has the cross-sectionalshape of a triangle with rounded corners so that the contour of recess1290 is shaped along two sides of the triangle and one corner. Thedimensions of recess 1290 are such that the sides of heating unit 1200-Hare in close contact with recess 1290. As also can be seen from FIG. 15,heating unit 500-H is fixed to casing portion 1260 via laser-welding.The laser welding is such that the other two corners of thetriangle-shaped heating unit 1200-a are welded to casing portion 1260.

Moreover, temperature monitoring and/or control unit or element 1230 bis laser welded directly on the top surface of heating unit 1200-H. Theother temperature monitoring and/or control unit or element 1230 a isstill attached to thermal bridge 1280.

Casing portion 1260 has a protection covering as already mentioned or ismade of roll-composite aluminum sheet which is provided on side of themedium with coverage of stainless steel.

An example application of one or more embodiments of the presentinvention generally relates to situations where a fixed temperatureneeds to be monitored or controlled and a maximum temperature must notbe exceeded, for example in household appliances such as dishwashers,dryers, and washing machines, small electrical appliances such ascoffeemakers, irons, steam generators etc. or in electrically monitoredwater heaters. Embodiments of the present invention may be used protectelectric heating elements.

The temperature monitoring and/or control unit may comprise one or moretemperature monitoring and/or control elements, such as, e.g., safetydevices.

Other variations to the disclosed embodiments can be understood andeffected by those skilled in the art from a study of the drawings, thedisclosure, and the appended claims.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” or “an” does not exclude aplurality.

A single unit or device may fulfill the functions of several itemsrecited in the claims. The mere fact that certain measures are recitedin mutually different dependent claims does not indicate that acombination of these measures cannot be used to advantage.

Determinations like measuring a temperature performed by one or severalunits or devices can be performed by any other number of units ordevices. For example, measuring a temperature can be performed by asingle temperature monitoring and/or control unit or by any other numberof different units. The determinations and/or the control of the heatingsystem for heating fluid media can be implemented as program code meansof a computer program and/or as dedicated hardware.

A computer program may be stored/distributed on a suitable medium, suchas an optical storage medium or a solid-state medium, supplied togetherwith or as part of other hardware, but may also be distributed in otherforms, such as via the Internet or other wired or wirelesstelecommunication systems. The term “computer program” may also refer toembedded software.

Any reference signs in the claims should not be construed as limitingthe scope.

One embodiment of the present invention relates to a heating systemcomponent comprising: a temperature monitoring and/or control unitcomprising a lower surface, and a carrier unit comprising an uppersurface. At least a part of said lower surface of said temperaturemonitoring and/or control unit is in thermal contact with at least apart of said upper surface of said carrier unit. Said lower surface ofsaid temperature monitoring and/or control unit and said upper surfaceof said carrier unit are attached to each other by means of a weldedseam, preferably by means of a laser-welded seam.

Aspects of the various embodiments described above can be combined toprovide further embodiments. Additionally, this application claimspriority to European Application No. 14173711.4-1602, filed Jun. 24,2014, and European Application No. 15173012.4, filed Jun. 19, 2015, theentire contents of which are hereby incorporated by reference. Aspectsof the embodiments can be modified, if necessary to employ concepts ofthe applications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled.

1-15. (canceled)
 16. A temperature monitoring and/or control unitcomprising a lower surface, wherein said lower surface of saidtemperature monitoring and/or control unit is connectable to a carrierunit by means of a welded seam.
 17. The temperature monitoring and/orcontrol unit according to claim 16, further comprising a lower parthaving a beveled edge, and wherein: said beveled edge is adjacent tosaid lower surface; said beveled edge comprises a bevel angle of lessthan 90°; and said welded seam is located essentially along said bevelededge.
 18. The temperature monitoring and/or control unit of claim 17,wherein said bevel angle ranges between 5° and 55°.
 19. The temperaturemonitoring and/or control unit of claim 16, wherein said temperaturemonitoring and/or control unit is configured to measure a temperature,to compare said temperature to a predefined temperature limit, and tooutput a control signal based on said comparison.
 20. The temperaturemonitoring and/or control unit of claim 19, wherein said control signalcomprises information on a desired switching state of a heating unit.21. The temperature monitoring and/or control unit of claim 16, wherein:said lower surface of said temperature monitoring and/or control unitcomprises at least one first protrusion and/or recess; said uppersurface of said carrier unit comprises at least one second recess and/orprotrusion; and said first protrusion and/or recess corresponds to saidsecond recess and/or protrusion.
 22. The temperature monitoring and/orcontrol unit of claim 16, wherein said lower surface of said temperaturemonitoring and/or control unit comprises a weldable aluminum alloy or analuminum-steel compound material.
 23. The temperature monitoring and/orcontrol unit of claim 16, wherein said upper surface of said carrierunit comprises at least one of aluminum alloys Al99.5, AlMg1, or AlMg3.24. The temperature monitoring and/or control unit of claim 16, whereinsaid temperature monitoring and/or control unit comprises at least onetemperature monitoring and/or control element having a lower surfacewhich is smaller than said lower surface of said temperature monitoringand/or control unit.
 25. A method for producing a temperature monitoringand/or control unit with a lower surface, the method comprising:beveling an edge of a lower part of said temperature monitoring and/orcontrol unit to obtain a beveled edge, wherein said beveled edgecomprises a bevel angle of less than 90°; and welding said lower surfaceof said temperature monitoring and/or control unit to a carrier unit,wherein said welding is carried out essentially along said beveled edge.26. The method of claim 25, wherein said welding comprises laser-weldingby employing a laser beam, wherein said laser beam is directedessentially perpendicular to a surface of said temperature monitoringand/or control unit.
 27. The method of claim 26, wherein said laser beamcomprises a power of between 0.5 kW and 1.5 kW.